I'm curious. You keep touting Oly and Bigma as being a great solution. But you've never used it. And, according to recent history when you had the opportunity to put your money where your posts are you bought Nikon not Oly. How is it you can keep recommending long range solutions - something you yourself are interested in - yet you go against your own advice. That seems a bit hypocritical. You tout in-body stabilization and 2x crop factor as being ideal yet you invest in the 2 systems that have neither. So again, I'll ask. Why didn't you invest in the system yourself instead of Nikon? Or why not sell off the canon gear. Sell your 500mm lens and it's easily enough to afford the Oly and Bigma with quite a bit of change left over. Surely there must be a reason you haven't followed your own advice

When it comes to IS you always want to have your cake and eat it too. On the one hand you state that you don't think it's very useful, and post lots of your hand-held shots to prove your point. On the other hand you seem think that stabilized bodies provide an advantage and post links to prove it.

If the former is true then the shots are meaningless because the IS isn't actually beneficial, and that photographer would have got equally good shots without IS. You need to decide which side of the fence you are on. :-)

The chances of me ever using such long lenses is remote in the extreme but hearsay suggests that some users of the very long lenses find even with a heavy tripod and wimberly head that a small breeze can introduce shake that the IS helps with a great deal. Of course the answer may lie on a continuum rather than be clear cut. Is a 10% improvement in usable shots worth the cost of IS? How about a 50%? You do use these lenses though. When you are out with your 500mm f4 IS do you have the IS on or off? Does it improve your keeper % on and off the tripod? At any rate your points are about handholding, and IS is not just relevant for handholding.

TCav,

I thought about this a bit. I am not at all sure that the LL posters are correct. I haven't studied optics at all. However I'm pretty sure you are not 100% correct either.

When you look through a 300mm lens on a crop body it shakes a lot. Zoom down to 70mm and the shake is much less. Your suggestion is that the amount of correction required is independent of focal length. This is in direct conflict with my experience - and I think most peoples too - how about it gang?

Your suggestion is clearly dissonant with the common rule of 1/equivalent focal length rule for handholding too. If the focal length didn't matter then there would be no need to reduce the shutter speed depending on the focal length.

It is also not simply related to the weight of the lens; clearly the weight of a zoom lens doesn't change depending on whether it is zoomed in or out. My 50 f1.2 L is pretty heavy, very close to my 70-300 but I don't see the same shake from it. Though of course bigger/heavier lenses are harder to hold and beyond a certain point it becomes impractical to even try to hand-hold the really big beasts.

However I can see your point that it might not be the case that you are equally likely to get a degree of displacement from a camera with a 50mm lens or one with a 500mm lens. So yes, linear displacement might be a factor too. But I can't see how that can be the whole story, otherwise the only factor at work is the weight of the lens, and experience says focal length is an important variable in this equation.

There are a couple of other factors to consider too. One point they make is that the benefit of in-lens IS is that it stabilizes what you see in the viewfinder; i.e. the image is stabilized before it reaches the camera.

On my 70-300 stabilized lens this is very apparent. Once the stabilizer kicks in the picture through the viewfinder is exhibits a great deal less shake. This makes it easier for the AF system and easier to compose the shot. The longer the focal length the more this is apparent. It is very easy for AF to drift off the subject at the best of times, if the image reaching the AF sensor is moving around then that will clearly be a problem unless they have some mechanism for compensating. From what I've read that is not the case.

I can claim to be neutral on this, because although I use Canon I don't use telephoto lenses much and don't feel very strongly attached to IS myself. After all I take 75%+ of my shots with a prime. It's a "nice-to-have" feature for me, as I say I prefer the 24-105 f4 IS over a 24-70 f2.8 non-IS, it's smaller, lighter, cheaper and because of the IS actually a better lens for hand-holding at f8, which is where I tend to use those lenses.

I can certainly see the attraction of having body stabilization for my primes which might improve the keeper rate of marginal shutter speed shots like 1/10s - 1/40s when using a 50mm lens. So for my personal needs an FX camera with body IS sounds quite nice. But for example if Sony were to produce such a camera it would be far less important in the overall decision to buy one than the quality and cost of the Zeiss and Minolta lenses v the equivalent Canons.

... Surely there must be a reason you haven't followed your own advice

Yeap I have sweet spot in that I still have several lenses looking for a good in-body IS (hopefully a full-frame and the only Reflex 500 with AF!):
-> Unlike you guys I enjoy collecting cameras and eventually an Oly too - Just watch this space...

There's a big hole in Luminous Landscape debate in that they left out a very important number: the SHUTTER !!!

-> Let assume the 8in displacement is correct for a moment - The only critical movement to correct is from the time the shutter open to when it closes right? and not the entire displacement so for example a 1/100s shutter speed would that be only .08 of an inch?

Let plays the devil advocate for a moment and we could even assume the in-body IS is more efficient than an optical one:
1. You can optically "see" the IS/VR doing their thing - Cool, but so what: aren't you just wasting the battery since everything the photographer "see" is actually irrelevant to what the sensor capture, and that the only time IS/VR is critical is when the photographer doesn't see i.e. when the mirror is flipped up and when the sensor capture the image which is no different than an in-body IS?
2. With an in-body IS the lens stay constant - With an optical IS/VR who know what else can alter the optical property of a lens when the optical block moves to compensate... and you can notice most non-IS lenses are sharper than the ones with IS
3. The "shake" meter in the viewfinder can actually be useful since one can guage how to minimize our own motion by watching it... :-)

I concede that I misspoke when I said "... and the focal length of the lens attached to the camera wouldn't have anything to do with the amount of shift required." The point I was trying to make is that shake happens, regardless of the focal length of the lens attached, and that longer lenses magnify the visual affect of shake, but not to the extent determined in the calculations you presented! There is no way that a 1° angular displacement of a camera/lens assembly equates to 54mm on a 16mm image sensor!

What I meant to say was "... the focal length of the lens attached to the camera wouldn't have anything to do with the amount of shift required in the formula you presented." I did not mean to imply that the amount of correction required is independent of focal length. I just meant that, for a lens with a 5.5° angle of view, an angular displacement of 1° shifts the image by 1/5.5 of the size of the image sensor, just as it would shift the image by 1/90 of the size of an image sensor, when using a lens with a 90° angle of view. This demonsrates quite clearly that longer lenses present a greater need for stabilization that shorter lenses, which is what you've said.

It appears that you have also responded to some of the comments that I have apparently removed from my earlier post, but I'll address them anyway. I stand by them; they just didn't make much of an argument in the discussion at hand.

Camera shake is induced mostly by the inherent system in the human body to continuallybalanceitself. When we brace ourselves against a fixed object, that system relaxes, and we shake less. Objects at rest tend to remain at rest, and objects in motion tend to remain in motion. In general, longer lenses weigh more than shorter lenses. When we hold a long lens, its mass tends to keep it from being moved around a lot, just as its mass would tend to keep it moving once it has started to do so. Our system of maintaining balance would have to fight against the mass of a large, heavy lens in order to shake it. Since the large, heavy lens doesn't want to be shaken (please excuse the anthropomorphization), the mass of the lens will impede our attempt to do so. Therefore, the weight of a lens would have the effect of damping camera shake. To be sure, since a long lens magnifies the impact of shake, we still see a great deal of shake when using a long lens, but we would see more shake from a 300mm lens that weighed 1 lb. than we would from a 300mm lens that weighed 10 lbs. That's the point I was trying to make about the weight of a lens damping the shake.

And, yes, I can see that optical image stabilization would present a stabilized image in the viewfinder, and therefore, the autofocus system might perform better thanif it had a non-stabilized image to work with. And that would be an argumentin favor ofOptical Image Stabilization.But an autofocus system might also simply be tuned to the focal length of the attached lens, since, as you know, lenses tell cameras what their focal lengths are (again, please excuse the anthropomorphization).